1. Field of the Invention
This invention relates to members having a plasma-polymerized film as a surface coating for use with media capable of recording and/or reproduction of information utilizing magnetism, light or the like, for example, casings or cartridges for video, audio and computer tape and disks.
2. Discussion of Prior Art
Various information recording/reproducing carriers including video cassettes, audio cassettes, computer cartridges, video floppy disks, and laser vision disks are of the design that a tape or disk-shaped recording/reproducing medium is received in a casing such that the medium may travel or rotate in the casing or recording/reproducing equipment. More particularly, within these recording/ reproducing carriers, the recording/reproducing medium moves in sliding contact with members constructing or disposed in the casing, and these members in the casing make mutual slide contact during operation.
In the case of video tape cassettes, for example, the cassette casing has received therein a recording medium in the form of video tape and various members including reels on which the tape is wound, brakes for locking the reels, and guide posts and tape guides for guiding the tape during operation. When the recording/reproducing equipment is loaded with the medium for operation, the video tape makes slide contact with the tape travel guide members such as guide posts and tape guides, and the reels make contact with reel-retaining leaf springs.
To ensure that the travel or rotation of the medium in the form of tape or disk be accurate, smooth and stable, these members have to meet the following requirements:
(A) a low coefficient of friction,
(B) sufficient abrasion resistance and surface hardness to minimize abrasion of the members and the tape which would cause dropouts, and
(C) antistatic properties to prevent build-up of static charge which would cause recording/reproducing malfunctions.
In the prior art, the casing members are formed from resinous material because of ease of molding and light weight. To meet the above requirements, the members are provided with antistatic coatings on the surface, replaced by abrasion resistant metal parts for the necessary portions, or provided with metal coatings. However, formation of an antistatic coating has problems including difficulty of coating a uniformly thin film and blooming. Partial replacement of the members by metal parts has problems including an increased number of steps, increased cost, and difficulty of processing a complex shape.
Under the circumstances, the inventors previously proposed to form plasma-polymerized films of organometallic compounds (Japanese Patent Application Kokai No. 222115/ 1983) and silicon compounds (Japanese Patent Application Kokai No. 222114/1983) on such members. For these films, nevertheless, only antistatic property is taken into account while no evaluation is made on dynamic friction during operation.